Optical Nanoantennas for Photovoltaic Applications

In the last decade, the development and progress of nanotechnology has enabled a better understanding of the light–matter interaction at the nanoscale. Its unique capability to fabricate new structures at atomic scale has already produced novel materials and devices with great potential applications in a wide range of fields. In this context, nanotechnology allows the development of models, such as nanometric optical antennas, with dimensions smaller than the wavelength of the incident electromagnetic wave. In this article, the behavior of optical aperture nanoantennas, a metal sheet with apertures of dimensions smaller than the wavelength, combined with photovoltaic solar panels is studied. This technique emerged as a potential renewable energy solution, by increasing the efficiency of solar cells, while reducing their manufacturing and electricity production costs. The objective of this article is to perform a performance analysis, using COMSOL Multiphysics software, with different materials and designs of nanoantennas and choosing the most suitable one for use on a solar photovoltaic panel.

Polarimetric and radiative transfer modelling of HD 172555

ABSTRACT The debris disc around HD 172555 was recently imaged in near-infrared polarized scattered light by the Very Large Telescope’s Spectro-Polarimetric High-contrast Exoplanet REsearch instrument. Here we present optical aperture polarization measurements of HD 172555 by the HIgh Precision Polarimetric Instrument (HIPPI), and its successor HIPPI-2 on the Anglo-Australian Telescope. We seek to refine constraints on the disc’s constituent dust grains by combining our polarimetric measurements with available infrared and millimetre photometry to model the scattered light and continuum emission from the disc. We model the disc using the 3D radiative transfer code hyperion, assuming the orientation and extent of the disc as obtained from the SPHERE observation. After correction for the interstellar medium contribution, our multiwavelength HIPPI/-2 observations (both magnitude and orientation) are consistent with the recent SPHERE polarization measurement with a fractional polarization p = 62.4 ± 5.2 ppm at 722.3 nm, and a position angle θ = 67° ± 3°. The multiwavelength polarization can be adequately replicated by compact, spherical dust grains (i.e. from Mie theory) that are around 1.2 μm in size, assuming astronomical silicate composition, or 3.9 μm, assuming a composition derived from radiative transfer modelling of the disc. We were thus able to reproduce both the spatially resolved disc emission and polarization with a single grain composition model and size distribution.

Electrowetting lens with large aperture and focal length tunability

The electrowetting lenses has attracted researchers in many fields, such as biology, beam shaping, and drug delivery. Previous research on electrowetting lens has focused on neither expanding the dynamic focal length range nor reducing the wavefront aberration. However, the properties with large numerical aperture and low aberration are also essential properties of lenses, and can promote their application. Therefore, we calculated the meniscus of the lens with different optical apertures, and subsequently, analyzed the relations among the focal length, wavefront aberration, and optical aperture. To expand the focal length range, we designed an electrowetting-based triple-liquid lens with a root-mean-square wavefront aberration error of less than 1/4 waves.

Enhancing the Capability of a Ground-Based Optical Telescope for Thai National Space objects Observation †

Nowadays, the space operations environment have to face with space safety problems because of the growing of space debris in resident of space objects (RSOs) that can cause a catastrophic collision. In order to prevent debris-related risks in operational orbit, ground-based passive optical telescope network were used as a primary equipment for space debris observation due to the lowest maintenance costs. Furthermore, in technical, a precise tracking (position and velocity) of space objects can be beneficial towards not only orbit determination but also estimation spacecraft collision probability especially, in Low-Earth Orbit regime. National Astronomical Research Institute of Thailand (NARIT) has long experience operate in an observatory to perform both passive & active optical instruments for astrophysics and space sciences missions. In this research, based on Thai National Space objects Observation (TNSO) project, we re-establish the basic understanding of satellite tracking, optical subsystem integration and demonstration a framework so as to enhance the capability of telescope servo control subsystem. We describe the specific solutions adopted for continuous tracking mode and the results obtained during the commissioning of an alt-azimuth mounting equipped with 0.7 meter optical aperture telescope. The observation system can be performed with negligible as continuous tracking error. This contribution will present some of the experimental results and plans for further measurement campaigns.

Imaging

Treating an imaging system as a linear system and use llinear system properties to d iscuss both coherent and incoherent imaging. Use a one dimensional pin hole camera to study the theory of incoherent imaging. Two different criteria, Rayleigh and Sparrow, are used to define the resolution limits of the camera. From the simple theory define the optical transfer function and the modulation transfer function as appropriate characterizations of complex imaging systems. A review of the human imaging system emphasizes tits idfferences with man made cameras. Coherent imaging is based on Abbe’s theory of microscopy. A simple 4f imaging system can be used to understand how spatial resolution is limited by the optical aperture and by controlling the aperture, we can enhance the edges of an image or remove noise intensity noise on a plane wave. Apodizing the aperture allows astronomers to locate planents orbiting distant stars.